Variable speed gear



Jul 21,, 1931; L, KAMB 1,815,475

VARIABLE SPEED GEAR Filed Nov. so. 1929 :5 Sheets-Sheet 1 a //vl//vTOR Lu/y/ Aambo by A lfhvey July 21,1931. f L. KAMBb 8 5,

VARIABLE SPEED GEAR Filed Ndv. 50. 1929 3 Sheets-Sheet 2 L u/g/ Kamba ,4 f/aFhey July 21, 1931. L YKAMBO 1,815,475

VARIABLESPEED GEAR Filed Nov. 30, 1929 3 Sheets-Sheet 3 W I Y v jwavrox BY M 218 lira/ma Y Patented July 21, 1931 .UNITED STA In a previous Patent, No. 1,711,791, of May 7, 1929, issued to applicant a course recording apparatus has been described for tracmg lowed by any vehicle traveling on land, at sea or in the air.

The said course-recording apparatus did comprise, amongst other devices a speed reducing gear having a graduall variable ratio of transmission, in. which t e variability of the ratio of transmission was obtained by varying the angle formed by the axles of a sprocket wheel and of a globular ribbed wheel, interposed on the transmisslon, and

meshing together. The present application has for its ob]ect certain improvements in the above said device for changing gradually the speed, WlllCll also greatly simplify the construction of the same.

And since said device can be evidently appliedwith advantage to many other apparatus Y and contrivances in which it may be desirable to have a gradually variable speed gear, ca- ;pable at thesame time of producing a re-v versal of the .movement, the improved device will hereinafter be described separately from the parts of the course-recording apparatus which, on the other hand, as it will be seen, do not undergo any material change owing to the improvements in the variable speed gear.

serve to illustrate by way of example a practical embodiment of the' improved variable speed gear according to the present invention:

Fig. 1 shows a longitudinal section of the gear and I Fig. 2 shows a cross section of it, the section of Fig. 1 bein made according to line AA of Fig. 2, an the section of Fig. 2 according to line B-B of Fig. 1.

Fig. 3 is a diagram which serves to explain the principle on which the variability of the transmission ratio is obtained.

Fig. 4 is a cross section through the rim of the driving wheel made at a larger scale; Fig. 5 shows in detail one of the pins'constituting the retractile teeth of the driving wheel, and

automatically, to a given scale, the course fol- I In the accompanying drawings, which LUIGI mno, or some, ITALY VARIABLE srnnn GEAR Application filed November 30, 1929, Serial No. 410,717, and in Italy December 3, 1928.

Fig. 6 shows the engagement between the driving wheel and the driven wheel.

In the example shown it is assumed that the movement is transmitted by a driving shaft 1 to a driven shaft 2, the two shafts being placed at right angles with respect to each other.

On the driving shaft 1 which revolves in the direction indicated by the arrow z, is keyed the driving wheel 3 fitted with one or more rows of retractile pins 4. In the drawin s only two of these rows are shown, althoug there are actually three, the third or central row being covered by the shaft 8 in Fig. 2.

In order to obtain smoothness of movement it is advisable that these pins be fitted so as to allow them to be pressed inwards and this can be obtained by means of a small spring (Fig. 5) wound around or placed,

under each of them 1n convenient recesses provided thereto. 1

. The driving wheel 3 is preferably enclosed in a casing 5 having the shape of a cylindrical drum and which carries also the bearings (not shown in the drawings) for the shaft 1.

Another casing 6 of spherical or spheroidal shape placed near the casing 5, contains in its inside the driven wheel 7 which is keyed on the shaft 8 revolving in bearings carried by a ring 9 the centre of which coincides with the point of intersection of the middle plane of the wheel 7 with the axis of the shaft 8. The ring 9 is in its turn mounted so that it can revolve inside a ring 10 fastened to the casing 6 and provided with a slot 11 through which passes a controlling lever or handle 12 by means ofwhich the wheel 7 can be rotated around a diameter of its. middle plane, indicated with m-m in the drawings.

Consequently, by rotating the handle 12 either by hand or with the means mentioned in the above said patents, the angle 0 between the middle planes and CC, Fig. 3, of the driving and driven'wheels, can be made to assume any desired value comprised between 0 and 90.

The wheel 7 has a grooved, or ribbed surface, with grooves or ribs parallel to the direction of its axis, and into these grooves engage the retractile pins 4 of the driving wheel 3. (See Fig. 6.) The retractile pins 4 are arranged in one or more rows on the rim of the wheel 3. Fig. 4 shows in transversal section two sets, each consisting of any movement to the wheel 7 By diminishing the .angle between the two axes in either direction, the wheel 7 starts revolving, and revolves at a speed which is inversely proportional to said angle, so that, when the two axes have become parallel, thus reducing to 0 the angle comprised between them, the peripherical speeds of the Wheels are equal.

As however the shaft'of the grooved wheel 7 becomes shifted, upon the transmission ratio being changed in the manner above described, it .is connected to the shaft 2, which is fixed against axial movement, by the following arrangement.

On the shaft 8 is keyed a conical wheel 13 which engages another conical wheel 14 keyed on the shaft 2, and as the axes of the two shafts '8, 2 pass through the centre of the ring 9, so when this ring revolves, the wheel 13 rolls around the wheel 14 as a planetary gear, maintaining its engagement therewith, so that the transmission occurs always in the same way whatever may be the angle 0 comprised between the two planes MM, CC. It will be apparent that with a reduction of speed obtained in this manner it is possible to overcome resisting torques applied to the driven shaft having practically any value whatever while maintaining constant the power applied to the driving shaft and the speed of rotation of it.

Having thus ,describedmy. invention, I claim as new and desire ,to secure by Letters Patent:

. 1., In a variable speed gear of the type in which the variation of the ratio of transmission and the reversal of the movement are obtained by varying the angle between the planes of the driving wheel and of an intermediary cross wheel, the combination of a driving shaft carrying a driving wheel provided with retractile teeth, a driven shaft and an intermediary cross shaft on which a ribbed wheel is mounted which engages with the said' driving wheel at various inclinations, a ring carrying the bearings of said cross shaft, which ring is mounted on its turn in such away that it can revolve on itself and two conical wheels engaging in any "position of the revolving ring, one of these wheels being keyed on the shaft of the ribbed cross wheel movable together with the ring,

When, as

the other being keyed on the driven shaft, which is fixed against axial movement.

2. A variable speed gear according to claim 1, in which the pins of the driving wheel are fitted elastically retractile thereon and are arranged in several rows.

3. Variable speed gear according to claim 1, in which the revolving ring carrying the ribbed cross wheel is provided with suitable eontrollin means allowing to shift as it may e required.

In testimony whereof I have afiixed my signature this 18th day of November, 1929.

LUIGI KAMBO.

the ring 7 

